请教一个翻译

大全-10-18、 There are fundamentally two possible changes in an economy that will each cause inflation unless other compensating changes also occur. These changes are either reductions in the supply of goods and services or increases in demand. In a prebanking economy the quantity of money available, and hence the level of demand, is equivalent to the quantity of gold available.

红色字体的句子如何翻译啊？这个句子我觉得好象问题啊，不符合GMAT的SC。

谁能帮分析一下。谢谢。

装语In a prebanking economy 主语 the quantity of money available（插入语, and hence the level of demand,） is equivalent to the quantity of gold available.

主干the quantity  is equivalent to the quantity

结构没错

逻辑有效性也没错